Sensor systems and methods utilizing adaptively selected carrier frequencies

ABSTRACT

A sensor system utilizing adaptively selected carrier frequencies is disclosed. The system includes a system bus, a bus master, and a sensor. The system bus is configured to transfer power and data. The bus master is coupled to the system bus and is configured to provide power to the bus and receive data from the bus. The sensor is coupled to the system bus and is configured to transfer data on the bus using an adaptively selected carrier frequency.

BACKGROUND

Automotive systems are complex systems that include computers andcomponents to operate and monitor automotive vehicles. The systemstypically include a processor that controls and monitors engineoperation and the like. The system generally operates various controlsystems that perform automotive functions. By monitoring, minor problemscan be identified and corrected before becoming major problems.

Automotive systems typically use a dual purpose bus to mitigate wiringand cost. The bus provides power to sensors and components and also isused for data transmission. Generally, attempts to improve providing ofpower degrade data transmission and, similarly, attempts to improve datatransmission degrade providing of power.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a sensor system that uses modulationfor data transmission.

FIG. 2 is a block diagram illustrating a sensor system configured toprovide modulated data at an adaptively selected carrier frequency.

FIG. 3 is a block diagram illustrating a master bus system configured totransfer modulated data at an adaptively selected carrier frequency.

FIG. 4 is a graph depicting an example frequency spectrum for anautomotive communication system.

FIG. 5 is a method for communicating over a bus using modulation andadaptively selected channel(s).

FIG. 6 is a method for receiving data and power over a system bus usingmodulation and adaptively selected channel(s).

FIG. 7 is a flow diagram illustrating a method for identifying asuitable channel for data transfer.

FIG. 8 is a flow diagram illustrating a method of removing channels froma list of prohibited channels.

FIG. 9 is a flow diagram illustrating a method to adaptively selectchannels during communication.

DETAILED DESCRIPTION

The present invention will now be described with reference to theattached drawing figures, wherein like reference numerals are used torefer to like elements throughout, and wherein the illustratedstructures and devices are not necessarily drawn to scale.

Systems and methods are disclosed that facilitate automotive systems andrelated systems. The communication between components, such as sensorsand controllers, is facilitated by modulating communications or datatransmission to selected frequencies.

FIG. 1 is a diagram illustrating a sensor system 100 that usesmodulation for data transmission. The system 100 can be used forautomotive systems and the like. A modulation technique at an adaptivelyselected carrier frequency is utilized for data transmission to enhancedata rates and mitigate power consumption.

The system 100 includes a plurality of sensors 102, a system interfaceor bus 106 and a bus master component 104. The master component 104,also referred to as the master side or bus master, provides power 112and transfers data 114. The power 112 is provided according to selectedlevels that typically correspond to a particular protocol, such as anautomotive protocol. The master component 104 can be configured to onlyreceive data or can be bidirectional, and send and receive data. Themaster component 104 is configured to demodulate received data 114 inorder to extract the demodulated data.

The received data 114 is at a first carrier frequency and is demodulatedusing a modulation technique agreed by and known to both the master andthe sensor. Additionally, the master component 104 can be configured tomodulate transferred data 114. The transferred data 114 is modulatedusing a second modulation technique agreed by and known to both themaster and the sensor, which can be the same as the first modulationtechnique. The modulation technique requires a carrier frequency anorder of magnitude greater than the data rate transmission. The mastercomponent 104 can be configured to perform clock and data recovery, forreceived data 114 without a clock signal. The sensor component 102 canbe configured to perform clock and data recovery, for received data 110without a clock signal.

Some examples of suitable modulation techniques that can be utilized forthe first and second modulation techniques include binary phase shiftkeying (BPSK), quadrature amplitude modulation (QAM), phase shift keying(PSK), and the like. Additionally, the suitable modulation techniqueincludes adaptive modulation wherein varied channels or frequencies canbe identified to facilitate transmission. Thus, for example, a noisychannel is not used.

The system bus 106 is configured to transfer data and power. The systembus is arranged with a suitable number of wires and types of wires. Inone example, the system bus 106 includes a pair of wires that are usedfor transferring data and power. In another example, the system busincludes three wires, wherein a first and second wire are used totransfer power and the first and a third wire are used to transfer data.

The plurality of sensors 102 includes a first sensor 102 ₁, a secondsensor 102 ₂, to an Nth sensor 102 _(N) and are collectively designatedas the sensors 102. The sensors 102 each receive power 108 ₁, 108 ₂, to108 _(N), collectively designated as 108. The power 108 is received fromthe system bus 106.

Further, the sensors provide or transfer data 110 ₁, 110 ₂, to 110 _(N))which are collectively designated as 110. The provided data 110 ismodulated according to the first modulation technique and at the firstcarrier frequency. The transfer data 110 is provided to the system bus106, after modulation. The sensors 102 can also receive data 110 fromthe system bus 106, which can include control information and the like.The received data 110 is demodulated according to the second modulationtechnique.

In one example, the bus master component 104 is configured to adaptivelyselect the carrier frequencies used by the sensors 102 and the busmaster 104. A list of available channels are identified and analyzed toidentify a channel suitable for data transfer using the system bus 106.

FIG. 2 is a block diagram illustrating a sensor system 200 configured toprovide modulated data at a selected carrier frequency. The sensor 200provides data or information using relatively low power levels.

The system 200 includes a sensor 202, a control component 204, a powersupply 206, a data pump 208, a modulation component 212, a couplingcomponent 210 and a receiver 214. The modulation component 212 is shownas a modulation component 212 a for outgoing or transmitting informationand a demodulation component 212 b for incoming or receivinginformation. The sensor 202 provides sensor measurements for one or morecharacteristics. The measurements can include information such astemperature, pressure, vibration, rotation, magnetic field measurements,and the like. The measurements can be related to tire pressure, antilockbrake systems and the like. The sensor 202 provides the sensormeasurements to the data pump 208. Additionally, the sensor 202 receivespower from the supply component 206.

The sensor 202 is operated by the control component 204. The sensor 202can be controlled to take measurements, determine type of measurementsto obtain, perform actions, and the like. The control component 204 isalso configured to initiate a change in carrier frequency. The change isinitiated using a suitable mechanism, such as being initiated by amaster bus component also coupled to the bus 106, an automatic switchbased on a pseudorandom mechanism synchronous to the master, and thelike.

The supply component 206 provides the power to the sensor 202. Thesupply component 206 obtains the power from a decoupled power signalprovided by the coupling component 210. The supply component 206 mayfilter or modify the decoupled power signal before providing it as thepower to the sensor 202.

The coupling component 210 decouples a bus signal from the system bus106. In an incoming direction, the coupling component 210 decouples thebus signal into the decoupled power signal and a decoupled data signal.

The modulation component 212, which includes 212 a and 212 b, isconfigured to perform modulation and demodulation of signals. Foroutgoing data transfer, the modulation component 212 a modulates apumped data signal from the data pump 208 using a selected carrierfrequency into a modulated sensor measurement signal. The carrierfrequency utilized is typically 5 or more times higher than the databandwidth. In another example, the carrier frequency utilized istypically 10 or more times higher than the data bandwidth.

For incoming data transfer, the demodulation component 212 b demodulatesthe decoupled data signal into a received data signal. The demodulationcomponent 212 b utilizes an incoming modulation technique, whichcorresponds to a modulation technique used to modulate the data. Theincoming modulation technique may also be the modulation techniqueutilized for outgoing data transfer. The demodulation component 212 bcan perform clock and data recovery. The demodulation component 212 bmay perform itself the clock and data recover or utilize a separateclock and data recover component.

The receiver 214 receives the received data signal and can performprocessing on the received data signal prior to providing the receiveddata signal to the control component 204. This may include errorchecking mechanism, address matching and the like.

It is appreciated that variations in the above components arecontemplated. In one example, the modulation component 212 b obtains thedata signal directly from the bus 106 without using the couplingcomponent 210 to decouple it from the power signal. Additionally, inanother example, the modulation component 212 a provides the modulateddata measurement signal directly to the bus 106 without using thecoupling component 210.

FIG. 3 is a block diagram illustrating a master bus system 300configured to transfer modulated data at an adaptively selected carrierfrequency. The master 300 transfers data or information using relativelylow power levels while also providing power. The provided power can beutilized by other components, such as sensors and the like.

The system 300 includes a bus master 302, a control component 304, apower supply 306, an optional data pump 308, a modulation component 312,a coupling component 310 and a receiver 314. The modulation component312 includes a modulation portion or component 312 a and a demodulationportion or component 312 b. The bus master 302 may generate controlinformation, configuration information, and the like and provide theinformation as a master signal. The master 302 is operated by thecontrol component 304.

In addition to generating the master signal, the master 302 controls thepower supply 306. The power supply 306 is regulated to generate buspower with suitable characteristics, such as voltage level, current,frequency range, and the like. The bus master 302 can also receiveinformation via the control component 304 from the receiver 314.

The data pump 308 drives or pumps the master signal into a pumped datasignal. The pumped data signal is modulated by the modulation component312. The modulation component 312 is configured to perform modulationand demodulation of signals. For outgoing information or configurationtransfer, the modulation component 312 a modulates the pumped signalfrom the data pump using an agreed upon outgoing modulation techniqueand an adaptively selected carrier frequency. The signal is provided asa modulated master signal. The carrier frequency utilized is typically 5or more times higher than the data bandwidth. Further, the carrierfrequency is adaptively selected by analyzing available channels andselecting a suitable channel and carrier frequency that yields suitablecharacteristics. These include an error count below a threshold value.The available channels can include a currently used channel.

For incoming data transfer, the modulation component 312 demodulates adecoupled data signal into a received data signal. The modulationcomponent 312 utilizes an incoming modulation technique, whichcorresponds to a modulation technique used to modulate the data. Theincoming modulation technique may also be the modulation techniqueutilized for outgoing data transfer.

The receiver 314 receives the received data signal and can performprocessing on the received data signal prior to providing the receiveddata signal to the master component 302.

In an outgoing direction, the coupling component 310 is configured tocombine the bus power with the modulated master signal and provide acoupled signal to the bus 106. The coupling component 310 is alsoconfigured to decouple a bus signal from the system bus 106. In anincoming direction, the coupling component 310 decouples the bus signalinto a decoupled data signal.

It is appreciated that variations in the above components arecontemplated. In one example, the modulation component 312 provides thedata signal directly to the bus 106 without using the coupling component310.

FIG. 4 is a graph 400 depicting an example frequency spectrum for anautomotive communication system. The graph 400 is provided as an exampleto illustrate adaptively selecting channels for data transfer andmodulation. It is appreciated that the graph 400 is provided as anexample and that other channels and/or frequency spectrums can beutilized.

An x-axis depicts frequency and a y-axis depicts signal distortionmagnitude H across the frequency spectrum. Here, there are four channelsdepicted, F1, F2, F3, and F4. It can be seen that channels F1, F2 and F4have relatively low distortions and are below a threshold 402. However,the channel F3 has a relatively large amount of distortion present thatexceeds the threshold 402. As a result, the channel F3 is deemed notsuitable for data transfer.

Over time, the distortions or noise present in the channels can vary.Thus, distortion measurement and analysis can be performed again, overtime to reevaluate the channels.

FIG. 5 is a method 500 for communicating over a bus using modulation andadaptively selected channel(s). The method 500 can be utilized forautomotive systems and the like. The modulation technique at anadaptively selected carrier frequency is utilized for data transmissionto enhance data rates and mitigate power consumption.

The method begins at block 502, where a channel is selected from a listof available channels. The selection of the channel is performedpseudo-randomly from the set of allowed channels.

Data is obtained for transmission at block 504. The data or informationcan be obtained from automotive sensors, vibration sensors, temperaturesensors, controllers, and the like. As described above, thedata/information can be from a sensor, a bus master, controller, and thelike. The information can include control information, measurements,data, and the like. In one example, the information includes automotivemeasurements, such as tire vibration.

A modulated signal is generated for the data at block 506 using themodulation technique and the selected channel. The signal is modulatedusing a carrier frequency associated with the selected channel. Thesignal includes data or information to be modulated and transmitted.

The modulated signal is combined with additional signals at block 508 togenerate a combined signal. The additional signals can include aregulated power signal, a preamble for clock recovery, othercommunication signals, non-modulated signals, and the like. A coupler orsimilar component can be utilized to combine the modulated signal withthe additional signals. It is appreciated that some variations of themethod 500 omit combining the signal with the additional signals.

The combined signal is provided to a system bus at block 510. Thecombined signal includes the modulated signal and typically complieswith bus requirements. The bus requirements may include upper and lowervoltage limits, upper and lower current limits, power limits, frequencyranges, and the like.

The combined signal can be utilized for power and data transfer by othercomponents connected to the system bus.

It is appreciated that the method 500 can be utilized by multiplecomponents, such as sensors, coupled to the bus. For example, fullduplex communication permits multiple components to provide the data onthe bus at the same time. A master or other component would needmultiple receivers or be configured another way to receive the multiplecommunications at the same time. Additionally, each sensor and/orcomponent transmitting on the bus utilizes a different carrierfrequency.

FIG. 6 is a method 600 for receiving data and power over a system bususing modulation and adaptively selected channel(s). The method 600 canbe utilized for automotive systems and the like.

The method begins at block 602, where a channel is identified from alist of suitable channels for data transfer. The master changes thechannel at fixed points in time, agreed by the sensor. The channelchange is done synchronously at the master and sensor side. Both switchto the same channel.

Some examples of suitable modulation techniques include, binary phaseshift keying (BPSK), quadrature amplitude modulation (QAM), phase shiftkeying (PSK), and the like. It is appreciated that other modulationtechniques can also be utilized.

A combined signal is obtained from a system bus at block 604. Thecombined signal includes power and data signals. However, it isappreciated that variations of the method 600 include obtaining thepower and modulated data signals as separate, not combined signals.

The combined signal is decoupled into power and modulated data signalsat block 606. A coupler/decoupler can be utilized to separate thesignals from the combined signal. It is appreciated that this block isomitted if the signals are already separated.

The modulated data signal is demodulated at block 608 to obtain data.The demodulation uses the selected channel and modulation techniqueselected above. The data can include information can be obtained fromautomotive sensors, vibration sensors, temperature sensors, controllers,and the like. Further, the information can include control information,measurements, data, and the like. In one example, the informationincludes automotive measurements, such as tire vibration. Clock and datarecovery may be performed.

The power signal is utilized for powering a component at block 610. Thecomponent can include a sensor, actuator, controller, and the like.

FIG. 7 is a flow diagram illustrating a method 700 for detecting oridentifying an unsuitable channel for data transfer. The method 700analyzes data validity on received channels and may prohibit usage ofsome channels.

The method 700 begins at block 702, wherein a list of channels suitablefor data transfer is obtained. The set S of channels suitable for datatransfer have corresponding carrier frequencies designated as S={f1, f2,. . . , fn}.

An error count or similar characteristic for the channels in S isidentified and/or updated at block 704. The characteristic, in oneexample, includes an error count per carrier frequency/channel and isdesignated C={c1, c2, . . . ci}, where T can include all possiblefrequencies. The error counters C are associated with invalid datareceived on channel ‘ci’. Typically, a bus master or other componentmaintains the error count. At the end of a given time period t_(sync),the master updates the relevant error counts based on received framesfrom other components on the bus, including sensor components. If thereis an error with a received frame, the error count for the carrierfrequency is incremented. If there is no error, the error count for thecarrier frequency is decremented, limited to 0.

A list of prohibited channels is obtained and/or updated at block 706.Initially, the list of prohibited channels is zero and the list isdesignated by P. The prohibited channels have corresponding carrierfrequencies designated as P={p1, p2, . . . , pm}. Channels havingcarrier frequencies with consecutive error counts above a thresholdvalue e are removed from the list S and added to the list P.

It is appreciated that the number of available channels and carrierfrequencies in S can decrease over time and result in none beingavailable. This is referred to as “starvation”.

FIG. 8 is a flow diagram illustrating a method 800 of moving channelsfrom a list of prohibited channels to the list of channels suitable fordata transfer. The method 800 can be utilized in conjunction with themethod 700 to mitigate “starvation” of available channels.

The method 800 begins at block 802 wherein a list of prohibited channelsP, as described above, has been created. The list of prohibited channelsis initially at zero, but may increase over time.

A prohibited period counter for the prohibited channels is identifiedand/or updated after a given time period, t_(sync), at block 804. Thegiven time period is described as being the same time period used in themethod 700, however it is appreciated that variation in the time periodused in block 804 are permitted.

In one example, a bus master keeps a prohibited period counter for eachof the channels in the prohibited list. The counter is incremented atevery time period.

One or more of the prohibited channels are reintroduced to the list ofavailable channels S at block 806 according to a reintroductioncriteria. A variety of suitable reintroduction criteria can be used toidentify channels to be added to the list of available channels S.

In one example, the prohibited channel is reintroduced to the list ofavailable channels S after a random time period. The random time isdoubled after consecutive failures. Thus, channels with consecutivefailures can still be placed back in the list S, however, such channelsmust wait longer for reintroduction. Upon success, the random time isreset to an initial value.

FIG. 9 is a flow diagram illustrating a method 900 to adaptively selectchannels during communication. The method 900 pseudo-randomly chooses achannel from the set S of channels suitable for data transfer.

The method 900 begins at block 902, wherein a bus communication systemis provided. The bus communication system can include one or moresensors, a bus master, and the like. The system utilizes modulatedsignals to transfer data and power using a single bus.

A list of available channels is obtained for a current time period atblock 904. The list of channels S includes a number of channels andcorresponding carrier frequencies, as described above with regards toFIG. 7. The list of channels can be maintained as shown and described inmethod 800, described above.

A channel of the list of channels is selected for the current timeperiod at block 906. The selected channel is typically varied from achannel used in an immediately prior time period. In one example, thecurrent channel is selected randomly.

Communications for the current time period are performed using the buscommunications system and the current selected channel at block 908.

The method 900 can be repeated for subsequent time periods to facilitatecommunication.

It is appreciated that the methods of FIGS. 5, 6, 7, 8 and 9 andvariations thereof can be combined and utilized interchangeably.

While the above methods are illustrated and described below as a seriesof acts or events, it will be appreciated that the illustrated orderingof such acts or events are not to be interpreted in a limiting sense.For example, some acts may occur in different orders and/or concurrentlywith other acts or events apart from those illustrated and/or describedherein. In addition, not all illustrated acts may be required toimplement one or more aspects or embodiments of the disclosure herein.Also, one or more of the acts depicted herein may be carried out in oneor more separate acts and/or phases.

It is appreciated that the claimed subject matter may be implemented asa method, apparatus, or article of manufacture using standardprogramming and/or engineering techniques to produce software, firmware,hardware, or any combination thereof to control a computer to implementthe disclosed subject matter (e.g., the systems shown in FIGS. 1, 2, 3,etc., are non-limiting examples of system that may be used to implementmethods). The term “article of manufacture” as used herein is intendedto encompass a computer program accessible from any computer-readabledevice, carrier, or media. Of course, those skilled in the art willrecognize many modifications may be made to this configuration withoutdeparting from the scope or spirit of the claimed subject matter.

A sensor system utilizing adaptively selected carrier frequencies isdisclosed. The system includes a system bus, a bus master, and a sensor.The system bus is configured to transfer power and data. The bus masteris coupled to the system bus and is configured to provide power to thebus and receive data from the bus. The sensor is coupled to the systembus and is configured to transfer data on the bus using an adaptivelyselected carrier frequency.

Another sensor system is disclosed. The system utilizes adaptivelyselected carrier frequencies and includes a system bus, a firstcomponent, and a modulation component. The system bus is configured totransfer power and data. The first component is configured to generatedata. The modulation component is configured to modulate a modulateddata signal from the generated data using an adaptively selected carrierfrequency and a modulation technique and to provide the modulated datasignal to the system bus.

A method of communicating over a system bus using an adaptively selectedchannel is disclosed. A selection mechanism is utilized to select achannel for data transfer from a list of available channels. Data ismodulated using the selected channel to generate a modulated datasignal. The modulated data signal is provided to a system bus.

In particular regard to the various functions performed by the abovedescribed components or structures (assemblies, devices, circuits,systems, etc.), the terms (including a reference to a “means”) used todescribe such components are intended to correspond, unless otherwiseindicated, to any component or structure which performs the specifiedfunction of the described component (e.g., that is functionallyequivalent), even though not structurally equivalent to the disclosedstructure which performs the function in the herein illustratedexemplary implementations of the invention. In addition, while aparticular feature of the invention may have been disclosed with respectto only one of several implementations, such feature may be combinedwith one or more other features of the other implementations as may bedesired and advantageous for any given or particular application.Furthermore, to the extent that the terms “including”, “includes”,“having”, “has”, “with”, or variants thereof are used in either thedetailed description and the claims, such terms are intended to beinclusive in a manner similar to the term “comprising”.

What is claimed is:
 1. A sensor system utilizing adaptively selectedcarrier frequencies, the system comprising: a system bus configured totransfer power and data; a bus master coupled to the system bus andconfigured to provide power to the bus and receive data from the bus; asensor coupled to the system bus and configured to transfer data on thebus using an adaptively selected carrier frequency; and a controllerconfigured to select a carrier frequency from a list of availablecarrier frequencies based on a performance criteria and communicate theselected carrier frequency to the sensor, and subsequently selectanother carrier frequency from the list of available carrier frequenciesbased on a change in the performance criteria.
 2. The system of claim 1,further comprising one or more additional sensors coupled to the systembus and configured to transfer data on the bus using the adaptivelyselected carrier frequency.
 3. The system of claim 1, wherein the sensoris further configured to modulate the data using a modulation techniqueat the selected carrier frequency.
 4. The system of claim 1, wherein thesensor is configured to receive power from the system bus.
 5. The systemof claim 1, wherein the bus master is configured to transfer master datato the bus using a second carrier frequency.
 6. The system of claim 5,wherein the second carrier frequency is varied from the adaptivelyselected carrier frequency.
 7. The system of claim 1, wherein thecontroller is configured to determine an error count associated with theadaptively selected carrier frequency as the performance criteria, andis further configured to select another carrier frequency from the listof available carriers frequencies if the error count exceeds apredetermined threshold.
 8. The system of claim 1, wherein the busmaster is configured to provide the power at a frequency varied from theadaptively selected carrier frequency.
 9. The system of claim 1, whereinthe transferred data includes automotive information.
 10. A sensorsystem utilizing adaptively selected carrier frequencies, the systemcomprising: a system bus configured to transfer power and data; a firstcomponent configured to generate data; a modulation component configuredto generate a modulated data signal from the generated data of the firstcomponent using an adaptively selected carrier frequency, and to providethe modulated data signal to the system bus; and a controller configuredto select a carrier frequency from a list of available carrierfrequencies based on a performance criteria and communicate the selectedcarrier frequency to the modulation component, and subsequently selectanother carrier frequency from the list of available carrier frequenciesbased on a change in the performance criteria.
 11. The system of claim10, further comprising a coupling component configured to combine themodulated data signal with one or more additional signals and to providea combined signal to the system bus.
 12. The system of claim 10, furthercomprising a receiver configured to receive a second modulated datasignal from the system bus, to demodulate the second modulated datasignal into a received data signal, and to provide the received datasignal to the first component.
 13. The system of claim 1, wherein theperformance criteria comprises a signal noise or distortion metric, andwherein the controller is configured to select a carrier frequency froma list of available carrier frequencies that have a signal noise ordistortion metric that is below a predetermined threshold.
 14. Thesystem of claim 13, wherein the controller is further configured toselect the carrier frequency from the list of available carrierfrequencies using a pseudo-random selection process.
 15. The system ofclaim 1, wherein the controller is configured to update the performancecriteria and update the list of available carrier frequencies based onthe updated performance criteria, and wherein the controller is furtherconfigured to subsequently select another carrier frequency from theupdated list of available carrier frequencies.